I-Mab (now NovaBridge Biosciences) to buy Bridge Health Biotech for $1.8 million upfront

I-Mab (Nasdaq: IMAB), now NovaBridge Biosciences, said on July 17, 2025 that it had signed a definitive agreement to acquire 100% ownership of Bridge Health Biotech Co., Ltd. (Bridge Health). Chief Executive Officer Sean Fu said "Advancing givastomig is I-Mab's top priority." The company presents the purchase as a way to strengthen the intellectual property around givastomig, its lead drug candidate.

The deal gives I-Mab rights to bispecific and multi-specific uses of the Claudin 18.2 (CLDN18.2) parental antibody used in givastomig. Those uses include bispecific and multi-specific antibodies and antibody drug conjugates (ADCs). The release also says the acquisition removes all royalty obligations on givastomig owed to Bridge Health and reduces the future milestones I-Mab would pay. It does not give the royalty rate or the size of the milestones removed.

Terms and timing

I-Mab will pay Bridge Health shareholders an upfront payment of $1.8 million. It will also make non-contingent payments of $1.2 million through 2027. Shareholders may receive further milestone payments of up to $3.875 million, subject to development and regulatory milestones. The company expects the transaction to close in the third quarter of 2025.

Sidley Austin LLP served as legal advisor to I-Mab. The release names no financial adviser, placement agent or other bank for the deal. It also does not give I-Mab's cash balance at the time of the announcement, so readers cannot see how the upfront payment compares with the cash on hand.

What givastomig is and what the data show

Givastomig, also called TJ033721 or ABL111, is a bispecific antibody that targets CLDN18.2-positive tumor cells. It conditionally activates T cells through the 4-1BB pathway in the tumor microenvironment, where CLDN18.2 is expressed. The company is developing it for first-line metastatic gastric cancers, with possible use in other solid tumors. ABL Bio is its partner. I-Mab is the lead party in the global partnership, and the two companies share worldwide rights equally, excluding Greater China and South Korea.

The release points to positive Phase 1b dose escalation data presented at the European Society for Medical Oncology Gastrointestinal Cancers Congress (ESMO GI 2025). Those data show an 83% objective response rate at the doses selected for dose expansion, in a study that combines givastomig with nivolumab, an anti-PD-1 checkpoint inhibitor, and chemotherapy. The escalation cohorts enrolled 17 patients. The release does not say how many patients responded, and it describes no comparison group.

The company says the responses were "rapid, durable and deepened over time," with a favorable overall safety profile. The release gives no duration of response and no count of adverse events. It also says the antibody binds CLDN18.2 more tightly than the antibodies used in approved CLDN18.2-directed therapies. The release does not publish the binding data behind that comparison.

What is still ahead

The first dose expansion cohort of 20 patients finished enrollment ahead of schedule, and the second cohort of 20 patients was nearly complete when the release was issued. The company expects topline results from the expansion study in the first quarter of 2026. Until those results are reported, the 83% figure remains a result from the escalation cohorts, not from the expansion.

Givastomig is still in an ongoing Phase 1b study. The release describes no regulatory filing and no approval timetable. It also names no competing program other than the approved CLDN18.2 therapies it mentions in passing.

For shareholders of the company, the release sets two dates: a closing in the third quarter of 2025 and topline data in the first quarter of 2026. Nothing in the release says what happens to the milestone and royalty terms if the closing slips or does not occur.

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